Process of treating cotton fabric and the product thereof



c 15, 1938. s. B. BIRD ET AL 2,111,486

PROCESS OF TREATING COTTON FABRIC AND THE PRODUCT THEREOF Filed Nov. 25, 1955 2 Shets-Sheet 1 INVENTORS ATTORN EU March 15, 1938.

s. B. BIRD ET AL.

PROCESS OF TREATING COTTON FABRIC AND THE PRODUCT THEREOF Filed NOV. 25, 1935 2 Sheets-Sheet 2 INVENTORS f M77) ATTORNEY5 .Patented Mar. 15, 1938 UNITED STATES PATENT OFFICE PROCESS OF TREATING COTTON FABRIC AND THE PRODUCT THEREOF Application November 25, 1935, Serial No. 51,446

6 Claims.

This invention relates to the treatment of cotton fabric and the product of such treatment.

Among the primary objects of our invention are to provide a simple, inexpensive, effective and easily controllable process for treating woven cotton fabric and tosecure a fabric which has the improved characteristics and properties hereinafter set forth.

Other and more specific objects and advantages will appear in the following description.

The fabric to be treated may or may not be bleached in a manner known to the trade. If bleached, it should be treated with diastofor, diasotase or an enzymic substance to remove as much of the grey sizing as possible, after which it is dried in the usual manner.

Then the fabric is run through a pair of nip rollers, known as a "padder or mangle, the bottom roll of which is sufficiently immersed in a dissolving solution of copper sulphate, ammonia and caustic soda to be described, so that by its rotation it brings up suflicient solution to penetrate the yarn of the fabric at the nip, or the fabric may first be dipped into the solution before entering the nip or in other known ways of impregnation. The nip squeezes out any excess solution which would naturally remain on the fabric. The fabric should be passed or drawn through the solution at a speed such as to prevent the formation of an appreciable amount of cuproammonium cellulose, due to the solvent action, so that after the squeezing of the nip, no cellulose appears on the surface of the cloth. Appreciable cellulose on the surface would tend to opacity and a streaked coating. The time of immersion should not be over approximately 2 seconds. The solution very largely dissolves the fuzz or projecting fibers, and puts the fibers of the body of the yarn into partial solution.

After the removal of the excess solution, the fabric is immersed in any suitable manner in a sulphuric acid bath, preferably of an acid strength of 7% by volume as giving the best drape or hand. More or less than a 7% solution may, however, be used, giving a relative- 1y softer hand or drape. The fabric should remain in the acid bath until all the partially dissolved cellulose and such slight quantity of dissolved cellulose as may be present, are precipitated or set. This usually takes a few seconds.

Washing in water now follows to remove. the acid and the salts of reaction, after which the fabric is dried and the fabric may remain in this state as long as desired. These operations may piece of fabric consumes.

be performed singly or in continuous succession, i. e., in range or continuously.

It is then mercerized in known ways, as, for example, by a caustic soda solution of in the neighborhood of from about to 30% concentration, the fabric being preferably drawn through the solution and a frame to maintain width. The pull of the drawing maintains length. An acid and a water wash now follow and the fabric is dried. Preferably this acid wash is preceded by a water wash to remove excess caustic soda solution.

The process is simple and'inexpensive and easily controllable' There is no contamination either of the cuproammonium solution or the caustic soda solution. The dissolving solution is stable. The final prduct is different from one which is treated only with the dissolving solution or only with the caustic soda solution or from one which is treated, first, with the caustic soda solution and then with the dissolving solution. It issheer, has an unusual appearance, lustre or finish not obtained by either treatment alone or by the reversal of the treatments, and other characteristics some of which will now be mentioned. The size of the openings or interstices between threads is definitely increased by the action of the solvent solution, the dissolved cellulose being removed without connecting the threads together. The mercerizing action shrinks the fuzzless thread still farther. The increase in size of openings increases the possibility of air flow through the fabric, this increase in porosity being highly desirable in the wearing apparel field to allow the body to breathe freely. The cloth is rendered more absorbent to moisture (also highly desirable) but at the same time shows a marked reduction in its properties attributed to capillarity. For example, a treated piece, if dropped into a beaker of water, will sink in ap-' proximately V to /7 of the time a normal finished dry, it releases or takes up a higher percentage of atmospheric moisture than normal fabric in the same length of time. However, if an end of a piece of the treated fabric is'immersed in a liquid, the time for the liquid to rise a specified When heated bone height, as an inch, is greater by about 17% in the case of the treated fabric. This is probably due to the removal of the fine fuzz, the partial solu- .50 tion of the cellulose enclosed in the cuticle of the Because no starching is required, the fabric is especially useful for curtains or other purposes when the fabric is subjected to the weather and action of the elements, the "hang" or "draping qualities being unaflected. Because it retains its stiflness and crispness, it outlives a normally finished fabric which becomes flimsy and raglike when wetted. It has a sheer pleasing appearance in contrast to coated materials. The cuticle is not ruptured or appreciably ruptured by the solvent and the cellulose is regenerated in a different physical state consisting of smaller micelles. While the regeneration of the cellulose tends to increase the randomness of the crystal orientation, the mercerization decreases the randomness of orientation without chemical change or alteration in the micelles, giving increased luster, firm hand, and increased tensile strength. The fabric thus resembles rayon without its objectionable, glossy luster, but with high tensile strength and a bloom and rayon-like hand which remain permanent. The threads slip on one another more easily, and when necessary,

I threads may be readily pulled out, making the fabric suitable for embroidered fabrics, imitation lace for scarfs and table-cloths, for example.

The treated fabric may be preshrunk or sanforize shrunk or unshrunk. It has decreased flexibility with increased resiliency, a property diilerentiating it from normal cotton fabric.

The following tables afiord a comparison of cloth treated according to the invention (Sample #4) with plain bleached cloth (Sample #1), with mercerized cloth (Sample #2) and with cloth treated with the dissolving solution (Sample #3), as to certain of the properties and characteristics mentioned.

Speed of regain and total moisture absorbed Length of Sample conditioning at 7012. and 66 re 11 vs lizimidity l1 #2 #3 #4 6.58 6.42 5.79 6.70 10 minutes 5. 48 6. 73 5. 89 6. 63

5. 63% (av.) 6. 58% (av.) 5. 84% (at) 6. 62% (av.)

6.96 7.09 0. 17 7.18 20 mmutes 5. 98 7. 41 6. 40 7. 08

minutes-.- 6.24 7. 49 6.41 7.47 40 6. 20 7. 72 6.62 7.36

SOminutes... 6.31 7.64 6. 62 7.66 6.33 7.90 6. 74 7. 65

minutes.. 6.33 7.66 6. 55 7. 64 6. 39 7. 92 6. 82 7. 58

After soaki n g in water for 10 minutes and (1 than squeezing.. 146.4 112.9 118. 7 107. 1 137. 7 114. 9 125. 1 103. 3

Swelling of were fibers in water Diameter of iibm (In Difl co Peres t can 11 (microns) swelling In In water air (30 min.)

Air porosity Cubic feet per minute Sample per square foot:

Average Cubic {m 1 41.0. 2 79.0. 3 64.0. 4 164.0.

Samples were conditioned for four hours in an atmosphere of 72 F. temperature and 65% relative humidity before testing.

As showing that the structure of the fibers of cloth treated in accordance with the invention is different, attention is directed to the sets of figures in the drawings. The first set is of fibers of warp threads of cloth of Sample #1 (Figure 1), of Sample #2 (Figure 2), of Sample #3 (Figure 3) and of Sample #4 (Figure 4). Figures 5 to 8 inclusive show fibers of filling threads of the said Samples #1 to #4. The magnification is 300 diameters.

This dissolving solution is of the following composition: copper, 19.3 grams per liter, ammonia 124 grams per liter, sodium hydroxide 24 grams per liter. A wetting agent is preferably added, such as Avirol, 1 lbs. to 400 lbs. of the solution. This is preferably added at the last step in the making of the dissolving solution.

The dissolving solution may be prepared as follows: Dissolve 60 lbs. of QOPDer sulphate in 116.50 liters of water, and add 52 liters of 26 B. aqua ammonia and agitate until the basic copper just formed is redissolved. Cool or allow to cool to about 15 0. Any iron present will quickly settle. Of this, pour 95.13 liters into a mixer and add 66.5 liters of 26 B. ammonia.

Dissolve 10.4 lbs. of caustic soda (76% No.20) in sufilcient water to make 15.2 liters and cool to about 15 0.; and add 29 lbs. of cracked ice. The copper sulphate and caustic soda are thus in substantially molecular proportions, i, e. two mols of the caustic soda to one mol. of the copper sulphate.

Pour the second mixture slowly into the first, agitating until thoroughly mixed, which lowers the temperature to about 15 C.

The process may be performed on jute, hemp, rayon and possibly on other vegetable fibers. It may also be carried out on any fabric, light or heavy, open or close weave, and composed of any weight or twist of yarn. It may be necessary to vary the length of treatment for different materials but this can be readily determined by trial.

On examination of the drawings it will be seen that the fibers of yarn treated in accordance with this invention are substantially as transparent as the fibers which have been subjected to mercerization alone, and that the treatment makes the fibers more smooth and straightened out, substantially free from twist, and more rod-like than tubular, as contrasted with the fibers in the natural state or with the fibers of yarn which has been only mercerized or only subjected to the dissolving solution.

What we claim is: I

1. The process of treating cotton cloth which comprises subjecting the cloth to a dissolving solution for a period from instantaneous to not over several seconds while retaining the structure of the cloth, said solution made from copper sulphate, ammonia and caustic soda with a ratio of two mols of caustic soda to one of copper sulphate, removing excess solution if any, setting the regenerated or partially regenerated cellulose, washing the cloth, drying the washed cloth, and subjecting the dried cloth to a mercerizing treatment. v

2. The process of treating cotton cloth which comprises subjecting the cloth to a dissolving solution for a period from instantaneous to not' over several seconds while retaining the structure of the .cloth, said solution made from copper sulphate, ammonia and caustic soda with a ratio of two mols of caustic soda to one of copper sulphate, removing excess solution if any, washing withan acid solution of a strength of about 7% by volume, followed by a water wash and drying, and subjecting the dried cloth to a caustic soda solution of a concentration of about 20% to 30%, followed'by an acid wash, a water wash and drying.

3. In the process of treating cotton cloth which comprises subjecting the cloth to a dissolving solution for not over approximately two and one-half seconds, said solution made from copper sulphate, ammonia and caustic soda with a ratio of two mols of caustic soda to one mol. of copper sulphate, removing excess solution it any, setting the regenerated or partially regenerated cellulose, followed by washing and drying, and subjecting the dried cloth to a mercerizing treatment. a

4. The process which comprises passing cotton cloth through a padder wetted with a dissolving solution of copper sulphate, ammonia and caustic soda, with a ratio of two mols of caustic soda to one mol. of copper sulphate, thereby subjecting the cloth to the solution and removing excess solution approximately instantaneously and substantially, subjecting the cloth to a setting solution followed by washing and drying, and subjecting the cloth to-a mercerizing treatment.

5. The process of treating cotton cloth which comprises subjecting the cloth to a dissolving solution made from copper sulphate, ammonia and caustic soda, with the ratio of two mols of caustic soda to one of copper sulphate, the concentration being substantially on the basis of 19.3 grams per'liter of copper, 24 grams per liter of caustic soda, and approximately 124 grams per liter of ammonia, the cloth being subjected to the solution of such concentration for a, period of from substantially instantaneous to not more than approximately 2 seconds, removing excess solution if any, treating the cloth with acid solution followed by water washing, and subjecting the cloth to a mercerizing treatment.

6. A cotton yarn the fibers of which are transparent, smooth, straight, substantially free from twist and more rod-like than tubular, as contrasted with natural fibers, and being substantially free from reprecipitated dissolved cellulose, which yarn has been treated with a dissolving solution for, a period of. from instantaneous to not over approximately 2% seconds, said solution consisting of copper sulphate, ammonia and caustic soda with aratio of two mols of caustic soda to one mol. of copper sulphate, the partially regenerated cellulose being set, washed and dried and then mercerized.

AMUEL B. BIRD. ARNOLD LEROY LIPPER'I'. 

